Waxed paper products are available and are often used in food contact applications. In general, waxed paper products are often manufactured by applying a melted wax to a paper substrate, allowing the wax to soak into the paper, and then cooling the coated paper product. This process is often referred to as “dry waxing” and can be carried out by converters who purchase the paper substrate in rolls, treat the paper substrate with melted wax, and then sell the waxed paper product. Exemplary waxes often found on traditional off line waxed paper products include paraffin wax, isoparaffinic wax, microcrystalline wax, and mixtures thereof, and can include other additives that improve wax sheet performance. The process for manufacturing a waxed paper product by “dry waxing” can be referred to as a two step process because the first step involves manufacturing of the paper substrate and the second step involves applying wax to the paper substrate.
Poly coating refers to a technique where a polymer that is solid under room temperature is placed in an extruder, heated, and extruded onto the surface of a paper substrate or paper product. Exemplary polymers used in poly coating include polyethylene, polypropylene, and polyester. Polyethylene polymer refers to a composition having a higher molecular weight than polyethylene containing waxes.